Introduction

          Currently, ST Chemical Corporation produces 50,000 metric tons of acrylic acid in the plant shown in Figure 1 that has a NPV of about $157 million after 10 years of operation. The reaction involved in the production of acrylic acid are:

C₃H₆ + 3/2 O_2$$--> C₃H₄O₂ + H₂O            (1)

                                 Propylene               Acrylic Acid

                             C₃H₆ + 5/2 O₂ --> C₂H₄O₂ + CO₂ + H₂O       (2)

                           Propylene                 Acetic Acid

C₃H₆ + 9/2 O₂ --> 3CO₂ + 3H₂O             (3)

                                 Propylene

          An increasing demand has prompted the proposed construction of a second acrylic acid plant. Several possible improvements exist for the second plant. A new catalyst will allow a significant reduction in LPS feed (from 992 kmol/h to 275 kmol/h). The possible use of a packed bed reactor for the new plant was also explored, but has shown poor contributions to plant economics. Improved use of heat integration and separation should also be considered. Important process constraints include the polymerization temperature of 90 ⁰C for acrylic acid in the separation section of the plant. The applicable temperature range of the reactor of 290 ⁰C to 330 ⁰C is also a constraint. Another important objective is to minimize the amount of water sent to the separation section as this will directly affect the profitability of the plant.

          The topology of the current process was first optimized and then parametric optimization of the process conditions provided the final NPV of $211 million for the optimum case.

Letter of Transmittal
Executive Summary
Introduciton
Results
Discussion
Conclusions
Recommendations
References